The paper reports a spectrophotometric methodology to determine the anthocyanin content in blood orange juices. The criterion of difference of absorbances at 510 nm in two aqueous solutions (pH 1 and pH 4.5) revealed the real concentration of free anthocyanins, using an absorption coefficient obtained from the purest cyanidin-3-glucoside standard. The quantity of pigments is expressed as concentration of cyanidin-3-glucoside, the most important anthyanin in blood orange juices. The method was applied to fresh and concentrated processed juices and was controlled by HPLC anthocyanin analysis in the same juices
A SIMPLE AND RELIABLE METHOD FOR DETERMINING ANTHOCYANINS IN BLOOD ORANGE JUICES - ResearchGate. Available from: http://www.researchgate.net/publication/257353238_A_SIMPLE_AND_RELIABLE_METHOD_FOR_DETERMINING_ANTHOCYANINS_IN_BLOOD_ORANGE_JUICES [accessed Apr 28, 2015].